package org.apache.lucene.analysis.standard;
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.TypeAttribute;
import org.apache.lucene.util.AttributeSource;
import org.apache.lucene.util.Version;
import org.apache.lucene.util.AttributeSource.AttributeFactory;
/**
* This class implements Word Break rules from the Unicode Text Segmentation
* algorithm, as specified in
* <a href="http://unicode.org/reports/tr29/">Unicode Standard Annex #29</a>
* URLs and email addresses are also tokenized according to the relevant RFCs.
* <p/>
* Tokens produced are of the following types:
* <ul>
* <li><ALPHANUM>: A sequence of alphabetic and numeric characters</li>
* <li><NUM>: A number</li>
* <li><URL>: A URL</li>
* <li><EMAIL>: An email address</li>
* <li><SOUTHEAST_ASIAN>: A sequence of characters from South and Southeast
* Asian languages, including Thai, Lao, Myanmar, and Khmer</li>
* <li><IDEOGRAPHIC>: A single CJKV ideographic character</li>
* <li><HIRAGANA>: A single hiragana character</li>
* </ul>
*/
public final class UAX29URLEmailTokenizer extends Tokenizer {
/** A private instance of the JFlex-constructed scanner */
private final StandardTokenizerInterface scanner;
public static final int ALPHANUM = 0;
public static final int NUM = 1;
public static final int SOUTHEAST_ASIAN = 2;
public static final int IDEOGRAPHIC = 3;
public static final int HIRAGANA = 4;
public static final int KATAKANA = 5;
public static final int HANGUL = 6;
public static final int URL = 7;
public static final int EMAIL = 8;
/** String token types that correspond to token type int constants */
public static final String [] TOKEN_TYPES = new String [] {
StandardTokenizer.TOKEN_TYPES[StandardTokenizer.ALPHANUM],
StandardTokenizer.TOKEN_TYPES[StandardTokenizer.NUM],
StandardTokenizer.TOKEN_TYPES[StandardTokenizer.SOUTHEAST_ASIAN],
StandardTokenizer.TOKEN_TYPES[StandardTokenizer.IDEOGRAPHIC],
StandardTokenizer.TOKEN_TYPES[StandardTokenizer.HIRAGANA],
StandardTokenizer.TOKEN_TYPES[StandardTokenizer.KATAKANA],
StandardTokenizer.TOKEN_TYPES[StandardTokenizer.HANGUL],
"<URL>",
"<EMAIL>",
};
private int skippedPositions;
private int maxTokenLength = StandardAnalyzer.DEFAULT_MAX_TOKEN_LENGTH;
/** Set the max allowed token length. Any token longer
* than this is skipped. */
public void setMaxTokenLength(int length) {
this.maxTokenLength = length;
}
/** @see #setMaxTokenLength */
public int getMaxTokenLength() {
return maxTokenLength;
}
/**
* Creates a new instance of the UAX29URLEmailTokenizer. Attaches
* the <code>input</code> to the newly created JFlex scanner.
*/
public UAX29URLEmailTokenizer(Version matchVersion) {
this.scanner = getScannerFor(matchVersion);
}
/**
* Creates a new UAX29URLEmailTokenizer with a given {@link AttributeFactory}
*/
public UAX29URLEmailTokenizer(Version matchVersion, AttributeFactory factory) {
super(factory);
this.scanner = getScannerFor(matchVersion);
}
private StandardTokenizerInterface getScannerFor(Version matchVersion) {
return new UAX29URLEmailTokenizerImpl(input);
}
// this tokenizer generates three attributes:
// term offset, positionIncrement and type
private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
private final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
private final PositionIncrementAttribute posIncrAtt = addAttribute(PositionIncrementAttribute.class);
private final TypeAttribute typeAtt = addAttribute(TypeAttribute.class);
@Override
public final boolean incrementToken() throws IOException {
clearAttributes();
skippedPositions = 0;
while(true) {
int tokenType = scanner.getNextToken();
if (tokenType == StandardTokenizerInterface.YYEOF) {
return false;
}
if (scanner.yylength() <= maxTokenLength) {
posIncrAtt.setPositionIncrement(skippedPositions+1);
scanner.getText(termAtt);
final int start = scanner.yychar();
offsetAtt.setOffset(correctOffset(start), correctOffset(start+termAtt.length()));
typeAtt.setType(TOKEN_TYPES[tokenType]);
return true;
} else
// When we skip a too-long term, we still increment the
// position increment
skippedPositions++;
}
}
@Override
public final void end() throws IOException {
super.end();
// set final offset
int finalOffset = correctOffset(scanner.yychar() + scanner.yylength());
offsetAtt.setOffset(finalOffset, finalOffset);
// adjust any skipped tokens
posIncrAtt.setPositionIncrement(posIncrAtt.getPositionIncrement()+skippedPositions);
}
@Override
public void close() throws IOException {
super.close();
scanner.yyreset(input);
}
@Override
public void reset() throws IOException {
super.reset();
scanner.yyreset(input);
skippedPositions = 0;
}
}